Optimal Connected Cruise Control Design with Time-Varying Leader Velocity and Delays

With the development of intelligent transportation system (ITS), owing to its flexible connectivity structures and communication network topologies, connected cruise control (CCC), increasing the situation awareness of the autonomous vehicle without redesigning the other vehicles, is an advanced cruise control technology attracted extensive attention. However, due to the uncertain traffic environment and the movement of the connected vehicles, the leader speed is typically highly dynamic. In this paper, taking the uncertain time-varying leading vehicle velocity and communication delays into consideration, an optimal CCC algorithm is proposed for both near-static case and general dynamic control cases. First, the analysis for discrete-time error dynamics model of the longitudinal vehicle platoon is performed. Then, in order to minimize the error between the desired and actual states, a linear quadratic optimization problem is formulated. Subsequently, in near-static control case, an efficient algorithm is proposed to derive the solution of the optimization problem by two steps. Specifically, the online step calculates the optimal control scheme according to the current states and previous control signals, and the off-line step calculates the corresponding control gain through backward recursion. Then, the results are further extended to the general dynamic control case where the leader vehicle moves at an uncertain time-varying velocity. Finally, simulation results verify the effectiveness of the proposed CCC algorithm.

Impact of lateral groundwater flow on hydrothermal conditions of the active layer in a high-Arctic hillslope setting

Modeling the physical state of permafrost landscapes is a crucial addition to field observations in order to understand the feedback mechanisms between permafrost and the atmosphere within a warming climate. A common hypothesis in permafrost modeling is that vertical heat conduction is most relevant to derive subsurface temperatures. While this approach is mostly applicable to flat landscapes with little topography, landscapes with more topography are subject to lateral flow processes as well. With our study, we contribute to the growing body of evidence that lateral surface and subsurface processes can have a significant impact on permafrost temperatures and active layer properties. We use a numerical model to simulate two idealized hillslopes (a steep and a medium case) with inclinations that can be found in Adventdalen, Svalbard, and compare them to a flat control case. We find that ground temperatures within the active layer uphill are generally warmer than downhill in both slopes (with a difference of up to ∼0.8 ∘C in the steep and ∼0.6 ∘C in the medium slope). Further, the slopes are found to be warmer in the uphill section and colder in the base of the slopes compared to the flat control case. As a result, maximum thaw depth increases by about 5 cm from the flat (0.98 m) to the medium (1.03 m) and the steep slope (1.03 m). Uphill warming on the slopes is explained by overall lower heat capacity, additional energy gain through infiltration, and lower evaporation rates due to drier conditions caused by subsurface runoff. The major governing process causing the cooling on the downslope side is heat loss to the atmosphere through evaporation in summer and enhanced heat loss in winter due to wetter conditions and resulting increased thermal conductivity. On a catchment scale, these results suggest that temperature distributions in sloped terrain can vary considerably compared to flat terrain, which might impact the response of subsurface hydrothermal conditions to ongoing climate change.

Automated optimum visualization system for construction drawing reading

The task of reading drawings on construction sites has significant efficiency and cost problems. Recent products utilising laser projectors attempt to address the issue of drawing comprehension by projecting full scale versions of the drawings onto 3D surfaces, giving an in-place representation of the steps required to complete a task. However, they only allow projection in red or green at a single brightness level due to the inherent constraints of using a laser-based system, which could cause problems depending on the surface to be projected on and the ambient conditions. Thus, there is a need for a solution that is able to adjust the visualisation parameters of the displayed information based on the surface being projected onto. This study presents a system that automatically changes the visualisation parameters based on the colour and texture of the current surface to make drawings visible under any planar-like surfaces. The proposed system consists of software and hardware, and the software algorithm contains of two parts 1) the optimisation run that computes and updates the visualisation parameters and 2) the detection loop which runs continually and checks if the optimisation run needs to be triggered or not. In order to verify the proposed system, tests on 8 subjects with 4 background surfaces commonly found on site were performed. The test subjects were timed to find 10 bolt holes projected onto the surface using the optimisation system, which was then compared to a control case of black lines projected onto a white background. The system allowed users to complete the task on the real-world backgrounds in the same time as the control case, with the system resulting in up to a 600% decrease in recognition time on some backgrounds.

Predicting People’s Motivation to Engage in Urban Possum Control

Initiatives such as education, incentives, and regulations are used to change people’s behaviour and thereby achieve policy objectives. Understanding and predicting the willingness of people to change their behaviour in response to an initiative is critical in assessing its likely effectiveness. We present a framework proposed by Kaine et al. (2010) for understanding and predicting the motivation of people to change their behaviour in response to a policy initiative. The framework draws on the marketing concept of ‘involvement’, a measure of motivation. Through application to a predator control case study, we show how the framework may be used to predict people’s responses to a policy initiative and how these predictions might help agencies develop strategies to promote behaviour change.

Numerical Analysis of the ACL, with Sprains of Different Degrees after Trauma

Nowadays, cruciate ligament injuries have increased in incidence, since practicing a sport or physical activity has become a trend in current societies. Although this lifestyle generates multiple benefits, as a consequence, injury has also increased. Due to its nature and complexity, the ligaments of the knee are those that are most frequently affected, mainly the ACL (anterior cruciate ligament). This tissue reacts to overexertion or movements out of range, either caused by the exercise itself or caused by trauma caused by the practice of physical activity, causing various degrees of sprain. Whatever the etiology of these injuries, they will require a therapy indicated for each degree of injury. This therapy initially entails immobilization of the affected area and later; physical therapy will be required to a lesser or greater degree. Commonly, in the physiotherapy of these injuries, rehabilitation exercises are prescribed, where the physiotherapist asks a patient to use equipment with an estimated weight. However, the effectiveness of a generalized therapy in this way does not always give the expected results. This is related to the fact that these therapies are standardized and do not consider some factors such as the remaining muscle fibres that are not directly affected by the sprain, which does not mean that they should not be considered. Therefore, in the present work, a biomodel of a human knee has been developed and used to evaluate numerically how the ACL acts under an external load, when there are different degrees of injuries, caused by trauma. Four case studies were considered: Case 1 (control case) where the ACL is healthy, Case 2 where the ACL presents a 1st-degree sprain, Case 3 where the ACL presents a 2nd-degree sprain, and finally Case 4 where the ACL presents a 3rd-sprain grade. After performing the analyses, in the control case, it was found that it presents a balance between tensile and compressive stresses. While in the 4th case, the most critical tensile stress decreases while compression stresses increase. This shows that the ligament, having considerable damage, no longer works as it should and can eventually damage the collateral structures. It was found that, when there was a sprain, where the continuity of the ligament is compromised, a second torsional moment occurs in the ACL which causes the tissue fibres not to act according to their normal physiology or in a healthy state. The results obtained from the present study provide the possibility of predicting where the following injuries will occur by considering the von Mises failure criterion. Likewise, they will allow to improve the therapeutic procedures considering not only the injured structure but also the system as a whole.